The invention relates to a new class of piperidine derivatives and to the use of these piperidine derivatives as stabilizers for synthetic polymers.
The excellent properties and wide variability in the obtainable properties of synthetic polymers have resulted in their widespread and increasing use throughout the world in various forms, for example as filaments, fibers, yarns, films, sheets, other molded forms, latexes and foams. However, the majority of the common synthetic polymers suffer from poor thermal- and photo-stability. For example, polyolefins and polyurethane elastomers frequently undergo severe deterioration when exposed to sunlight or ultraviolet radiation; polyvinyl chloride and polyvinylidene chloride can be degraded and discolored by the action of light and heat; with the elimination of hydrogen chloride; and polyamides are also frequently subject to photo-deterioration. Various stabilizers have been used in the past to overcome these difficulties, examples including: benzotriazole and benzophenone derivatives for polyolefins; phenolic compounds and benzophenone derivatives for polyurethanes; and lead salts (e.g. basic lead silicate and tribasic lead maleate) or organotin compounds (e.g. dibutyltin laurate and dibutyltin maleate) for polyvinyl chloride and polyvinylidene chloride. However, many problems still remain and thus there is still a need for effective stabilizers.